Transcript Module 3

Virginia Department of Education
Module Three
Topic 1: Laws of Nature
Topic 2: Vision and Driving
Topic 3: Vehicle Reference Points and Establishing
Lane Position
Topic 4: Basic Maneuvering—Steering, Braking and
Vehicle Balance
Gravity
Topic One
How Laws of Nature Affect
Vehicle Balance & Weight
Load Transfer
Kinetic
Energy
Momentum
Inertia
Gravity (gn)
Gravity is the natural force that constantly pulls all
things to the earth and affects an object’s weight
Center of Gravity is a point where the mass of the
vehicle is concentrated and balanced
The higher the center of gravity, the more
unstable the vehicle becomes
When a driver brakes, accelerates, or corners, the
G forces are amplified
Kinetic Energy (KE)
The Energy of Motion
Kinetic energy is the energy an object possesses due to its
speed, or velocity (v) and its mass (m) : KE = 0.5 ∙ m ∙ v2
The faster the object moves, the more energy it collects
A heavier moving object will have more kinetic energy
than a lighter object moving at the same speed
A vehicle’s kinetic energy can be overcome by brakes,
friction, air resistance and gravity
Momentum (p)
Momentum refers to the quantity of
motion an object has, measured in
kg ∙ m/s
Formula: p = m ∙ v. The more mass
and more velocity an object has, the
more momentum
The white truck and the dump
truck are traveling at the same
speed;
Which vehicle has more
momentum? Why?
Change in momentum is called impulse;
the magnitude of impulse is based on the
amount of opposing force and the
timespan over which that force is applied.
Inertia
A Vehicle’s
Possible
States of
Motion
• Slowing down or Stopping
• Accelerating or Cruising
• Turning towards the Left
• Turning towards the Right
Inertia: an object’s tendency to resist any change in
its state of motion. How is inertia affecting the
positions of the people on the rollercoaster?
How is inertia affecting the
position of the person driving the
vehicle around the hairpin turn?
Inertia
(cont.)
When driving through this
curve, inertia creates the
sensation that you are
being pulled toward the
outside of the curve
Why?
Because you are traveling in a straight line, and
inertia wants to keep you going in a straight line
Controlling Vehicle Balance
Changing the Vehicle’s Center of
Gravity
Automobile
Chassis
What transfers weight from one
point of the vehicle to another?
• Acceleration
• Deceleration/Braking
• Steering Input/Cornering
• Surface Traction
Pitch
Roll
Yaw
Controlling Vehicle Balance
Steering Input
Click the link to watch this video of a professional stunt car driver use the,
“shuffle,” or “push-pull-slide” steering method :
Steering Input Video
Bounty Driver. (2014, June 20). Bounty Driver: Shuffle Steering Serpentine [Video file]. Retrieved from https://www.youtube.com/watch?v=1iSDqz6Bsqo
Controlling Vehicle Balance Pitch
“Pitch”
Vehicle Shifts Weight from
Front to Rear or Rear to Front
Forward Pitch
Backward Pitch
Release
Gas Pedal
Release
Brake
Brake
Accelerat
e
Slowing
down shifts
weight to front
tires
Speeding
up shifts
weight to
rear tires
Changing
Weight From
Rear to Front
Changing
Weight from
Front to Rear
Which is demonstrated above?
a). Forward Pitch
b). Backward Pitch
Controlling Vehicle Balance
Roll - Vehicle Shifts Weight from Side to Side
Three Factors that Factor in Creating
Vehicle Roll:
• Steering Wheel Movement: Sudden
jerky steering will throw the vehicle’s
weight to the inside tires of the
direction you steer
• Brake Application: Certain
braking/steering combinations can be
used to minimize roll while navigating a
sharp or long turn
• Grade of the Road: Although
interstates are mostly flat, smaller roads
sometimes slope downward on the
sides with the highest point in the
middle
Controlling Vehicle Balance
Yaw
Vehicle Rear-Load Transfers to the Left, Right, or Back and Forth
Factors that Affect Rear-Load
Transfers to the Right/Left:
• Sudden braking
• Sudden/excessive acceleration
• Sudden/excessive steering
• Traction loss to either the left or right
rear tire
• Road is tilted to either the right or left
This race car is making a left turn at a
high speed on a loose, dirt road which
has resulted in yaw to the left
Topic Two
Vision and Driving
Figure 1
Vision
The eyeball’s ability to distinguish the
number, shape, and color of an object.
Perception
How we interpret and understand
information gathered by any of the five senses.
What do you see?
Your Eyes are Critical to Driving
Drivers Base Driving Decisions on:
• About 90% on what they see
• About 10% of all on what they hear
or feel
Drivers:
• Search at least 20 seconds ahead in
your path of travel to evaluate the
situation and make good decisions
about speed, lane position, signs,
signals, markings, and potential
hazards
What Kind of Visual Input is Relevant to
the Driver?
Information that dictates or could affect how you
navigate your path of travel
Signs, Traffic
Signals, and
Lane
Markings
inform
drivers of:
• What they are expected to do
• What they are prohibited from
doing
• Changes in road/lane structure
• Potential hazards
• Location of common public
destinations
What Kind of Visual Input is Relevant to
the Driver?
Information that dictates or could affect how you
navigate your path of travel
Surrounding
Driving
Environment
and
Potential
Hazards
• Relative location, direction and
speed of other vehicles
• Displays of aberrant behavior by
other drivers
• Weather and road conditions
• Presence of/areas where
pedestrians, children, and animals
may be
Dothetest.(2014, December 26). Test Your Awareness: Do The Test [Video file]. Retrieved from
https://www.youtube.com/watch?v=Ahg6qcgoay4
Want to become a good driver?
You have to spend TIME
behind the wheel and actively
PRACTICE visual searching
skills!
“The eyes don’t tell the
brain what they see;
The brain tells the eyes
what to look for.”
The Three Visual Fields
Focal Vision
• 1.5 – 3º in the center of vision field
• Allows you to read/see details
Paracentral
Vision
• 8º in the center of the vision field
• Allows you to maintain path of
travel
Peripheral
Vision
• More sensitive to light and motion
• Orients individual to environment
Diagram of the Human Field of Vision
Visual Testing
Visual acuity tests measure
the level of detail your eyes
can see, (individually, and
together), in optimal light
conditions
Nearsighted: Able to see near things
more clearly than distant ones
Farsighted: Able to see distant
things more clearly than near ones
Seeing at Night
Hazards
Lack of light
drastically
reduces field of
vision, visual
acuity, depth
perception and
color recognition
Nocturnal and
crepuscular
wildlife become
active
Inner and outer
sources of
concentrated
light cause glare
People driving at
night are more
likely to be
intoxicated
People driving at
night are more
likely to be
fatigued
Seeing at Night: Compensation Strategies
Darkness
• Drive slower to allow more time to react
• Use Focal and Paracentral Vision
Glare
• Oncoming headlights: Avert your gaze to line painted on right side of road
• Internal light: keep it dark in the vehicle when it’s dark outside
• Sunbeams: keep windows, headlights, and signal lights clean inside and
out
Animals
• Use your high-beams on rural roads
• Pay attention to animal crossing signs
People
• Watch for erratic driving behaviors from other vehicles on the road
• Stay away from drivers exhibiting signs of distraction, intoxication, or fatigue
Other Factors that Affect
Visual Perception
Glare
Fatigue
Drugs/Alcohol
Weather
Darkness
Speed
Inattention
Smoke
Age
Dirty Windshield
Poor Windshield
Wipers
Poor night vision
Night Blindness
Speed Affects Vision
Hazards that increase with increased speed
• Drivers have less time to see and react
• Minor steering movements cause exaggerated vehicle
movements and weight shift
• Speed distorts and reduces Peripheral vision up to 90%
Compensation Strategies to use at Higher Speeds
• Train your eyes to look farther ahead—you’re covering ground
faster
• Allow more space between your vehicle and others
• Actively move your eyes from one side of the path of travel to the
other to search for relevant information and hazards
Are these line parallel?
Need both eyes to perceive depth (3D distance)
Allows you to judge gaps, speed, and distance of other
vehicles and hazards in the traffic environment
Essential when passing, approaching a vehicle or hazard;
turning, merging, and crossing intersections
To judge the distance between vehicles, look at where the
tires contact the road, not the body of the vehicle
Driving Mistakes that Indicate
Poor Depth Perception
Stopping too far from the stop line
or intersection
Stopping too close to vehicles ahead
Moving into gaps that are too small
Looking for gaps that are larger than needed to
perform a maneuver
Following other vehicles at
unsafe following distance
Hitting parked cars
when parking
Having “close calls” when entering traffic, passing, etc.
Ways to Improve Your Field of Vision
Clean
windows—inside
and out
Remove objects
that interfere
with vision
Clean vehicle’s
outside lights
and be sure
they work
Keep sunglasses
and windshield
scraper in
vehicle
Inspect wiper
blades for
damage and
effectiveness
Adjust mirrors
properly
Establishing a Safe Lane
Position
Line of sight
Targeting
Blind Spots
Lane Positions
Vehicle Reference Points
Line of Sight (LOS)
Line-of-sight is the visible path of travel from your
vehicle to the target area
When something obstructs your LOS, you may need to
adjust your speed and/or position until it is clear again
Path-of-Travel (POT)
Path-of-Travel is the series of continuous
positions your vehicle will occupy while
traveling toward your target area
Selecting a Target
Target
• Specific object
• Located straight
ahead in the center
of your path of travel
• Near visual field limit
• Steer towards
• Changes to
whatever appears in
the center of your
path of travel
Identify the target in this
driver’s path of travel
Do not stare at or fixate your
gaze on the target itself…
The Target Area
Rather than
focusing directly on
the Target,
continuously scan
to the left and right
of it (the Target
Area) for relevant
information and
potential hazards
Target Area
Using Lane Position to Maximize
Your Line of Sight
12 ft.
6 ft.
Lane positions are
based upon an
average lane size of
12-feet wide, and a
vehicle 6-feet wide
Select the lane
position that
gives you the
best line of sight
and safest path
of travel
This Diagram
shows the three
basic lane
positions drives
can use
1
2
3
Lane Position 1
2-3 Feet
2-3 Feet
Positioned in the center of lane with an equal
buffer of space on either side
Standard Vehicle Reference Points for Lane
Position 1
LEFT Reference Point
3 feet from pavement
line or median
RIGHT Reference Point
3 feet from pavement
line or median
•
•
•
Relates a part of the vehicle to some part of the roadway
Know your vehicle placement within a lane at all times
Maneuver in confined places
Lane Position 2
3-6 Inches
Allows for additional space to the right of the vehicle. Used
to prepare for a left turn or when avoiding a problem to the
right of the vehicle.
Standard Vehicle Reference Points for Lane
Position 2
LEFT Reference Point:
Vehicle is 3-6 inches
from the pavement
line or median
Preparing to
make a left-hand
turn
Determining
position for parking
on the left side of a
one-way street
RIGHT Reference
Point: Vehicle is 3-5
feet from curb,
pavement line, or
edge of road
Lane Position 3
3-6 Inches
Allows for additional space to the left of the
vehicle. Used to prepare for a right turn or when
avoiding a problem to the left of the vehicle.
Standard Vehicle Reference Points for Lane
Position 3
LEFT Reference
Point: Vehicle is 35 feet from the
pavement line or
median
RIGHT Reference Point:
Vehicle is 3-6 inches
from curb, pavement
line, or edge of road
Preparing to make
a right-hand turn
Determining
position for
parking on the
right side of the
street
Blind Spots of Pavement Around Your Vehicle
~16 feet
~9 feet
~48 feet
~6 ft.
~16 feet
~6 ft.
~3 feet
~16 feet
In the figure above, the green cars represent the size and areas
of pavement that the driver of the white car cannot see.
Standard Vehicle Reference Points:
Front Limitation
2. The driver should
look out the right front
window and allow the
vehicle to creep
forwards until the white
line is directly under the
passenger side mirror.
1.
1. As the vehicle
approaches the white
stop line, the driver will
lose sight of the
segment of line directly
in front of the vehicle:
so how does the driver
know when to stop at
the right place?
3.
2.
3. This reference point will
help you direct your vehicle
to a stop, with the nose of
the bumper positioned just
over the beginning of the
stop line.
Standard Vehicle Reference Points:
Rear Limitation
1.
1. When you look
back over your right
shoulder, the curb
should appear to
intersect near the
lower right side of
the right rear
window
2. When you look
back over your left
shoulder, the curb
should appear to
intersect with
the lower middle of
the left rear window
3.
2.
3. Using these
reference points will
allow you to back up to
a curb, leaving an
appropriate distance
between it and your
bumper
Topic 4
Basic Maneuvers – Steering and Braking
Holding the upper half of the wheel can result in excessive
steering, air bag injuries, and upper body fatigue
Benefits to keeping your hands on lower
half of the wheel:
• Puts the body in a natural position with
relaxed shoulders
• Promotes balanced control of the
steering wheel, reducing excess motion
• Improves stability by lowering the body’s
center of gravity
• Prevents arm injury if the airbag deploys
Hand-to-Hand/Push-Pull Steering
Hand-to-Hand Steering/Push-Pull
To turn RIGHT:
Left hand pushes
up from 8 o’ clock
to 11 o’ clock
Right hand pulls
down from 1 o’
clock to 4 o’ clock
Hand-Over-Hand Steering
Used at Speeds below 15 mph
Used for slow, tight turns - Arms cross on the top 1/3
of the wheel until desired path of travel is reached
Left Turn/left hand
Left hand pulls down,
then reaches up to
about the o’clock
position and continues
to pull 11-12 down to
the left
Left Turn/right
hand
Right Hand pushes up
to about the 11
o’clock position
One-Hand Steering
Backing straight-hand holds top of
wheel
• Backing a trailer--hand
holds bottom of wheel
Covering the Accelerator
Used for a smooth transition from braking to
accelerating
Allows the vehicle to coast which may speed
up or slow down the vehicle
Permits the driver to be prepared for any
needed acceleration
Acceleration Techniques
Progressive,
Smooth
Acceleration
Thrust
Acceleration
• Heel pivots foot from the brake pedal to
the accelerator
• Gently apply pressure to the
accelerator pedal to gradually increase
speed to minimize backward pitch and
maintain vehicle balance
• Typically used when passing or merging
into higher speed traffic
• Greater pressure is applied to
accelerator pedal to rapidly increase
speed without losing tire traction
Braking Techniques
Smooth
Braking
Technique
• Is a trait of a skilled driver
• Saves gasoline, and wear and tear on
the brake system and tires
• Use ball of your foot to press pedal
Methods to Reduce Speed
1. Release the
Accelerator Pedal
• Most frequently used
method to slow
vehicle speed
• Gradually reduce
pedal pressure to
avoid abrupt
changes in speed
Methods to Reduce Speed
2. Controlled Braking
•Check the rearview mirror for vehicles
coming up quickly behind you
•Release accelerator and gradually apply
smooth, steady pressure on the brake pedal
•For a smooth stop, gently ease off the brake
a few seconds before stopping to reduce
the vehicle’s weight shift so the car does not
pitch forward then backward during the
final phase of stopping
Methods to Reduce Speed
3. Threshold Braking in an Emergency
•Slows the vehicle as quickly as possible
without locking brakes or losing traction
•Release accelerator while checking for traffic
behind you
•Exert forceful pressure on the brake pedal;
you will feel the vehicle’s weight shift forward
•If you feel the wheels beginning to slide, ease
off of the brake pedal so the tires can start
rotating again
Methods to Reduce Speed
4. Trail Braking
•Used for sharp turns
•Occurs at the transition point where
you slightly reduce pressure on the
brake pedal to allow the vehicle to
begin to regain speed before applying
the accelerator
Methods to Reduce Speed
1. Use controlled braking prior to
reaching the curve
2. Begin easing off brake, and trail
brake with very light pressure until
halfway through the turn,
3. Accelerate out of the turn
Speed Limit
A speed limit is the maximum legal speed you
can travel on a road under ideal conditions.
You may drive slower than the posted speed,
but it is illegal to drive any faster. By law, you
must drive slower if conditions such as road
construction or bad weather make the posted
speed unsafe. It is illegal to use a radar
detector in Virginia.
58
Maximum speed limit for passenger vehicles and
motorcycles (unless posted otherwise)
59
Type of Highway Zone
Speed Limit
Interstate highways in certain rural areas
70 mph
Non-rural interstate highways, public roads
not part of the interstate system
55 mph
Rural rustic roads
35 mph
School, business and residential zones (You
are required to travel 25 mph in a school
zone only when indicated by sign or signal.
Otherwise maintain the posted speed.)
25 mph
Stopping Distance
Three factors determine the distance that it takes to
stop your vehicle:

Perception time: The time it takes you to recognize a
hazard.

Reaction distance: The distance your vehicle travels
between the time you recognize a problem and the
time you apply the brakes.

Braking distance: The distance your car travels after
you apply the brakes.
60
Average stopping distance on
dry, level pavement
Source: Code of Virginia section 46.2-880
61
Speed Quiz
1.
Can you drive slower than the posted speed
limit?
2.
Do you have to go 25 mph in a school, business
or residential zone?
3.
What is the speed on a rural highway?
4.
Can you assume that the maximum speed limit
on all public roads is 60 mph?
62
True or False
63
5. When traveling 65 miles per hour on dry, level pavement, it
takes the average vehicle over 500 feet to stop.
6. The maximum speed limit for passenger vehicles and
motorcycles on rural rustic roads is 35 mph (unless otherwise
posted)
7. The maximum legal speed you can travel on the road in wet
conditions is the speed limit.
Stopping
64
Describe at least 10 situations that you
must always stop your vehicle
Check Your Knowledge
65
1.
At flashing red signals, you must always stop your vehicle.
2.
A law enforcement officer signals for you to stop your
vehicle. You ignore the officer's signal and the officer pursues
you. As a direct result of the pursuit, the officer is killed. You
will be:
3.
When a school bus is loading or unloading passengers and
the signals are not on, you do not have to stop.
Anti-Lock Braking System (ABS)
ABS allows maximum stopping force without
locking up the brakes (skidding)
If standard brakes are applied too hard, the
wheels "lock" or skid, and you lose steering
control.
Anti-Lock Braking System (cont)
If steering control is lost, the vehicle skids in a
straight line wherever it is going
ABS is an anti-lock/anti-skid brake system that
allows the driver to steer during hard braking
Anti-Lock Braking System (cont.)
The ABS warning
will come on when
there is a problem
with either the
ABS brake system,
normal brake
system, or the
brake fluid is low
in the master
cylinder or the ABS
brake system
To find out if a
vehicle is
equipped with
ABS, turn on the
ignition and
check the
instrument panel
for the ABS
indicator light
Practice Activating ABS
In a parking lot, go 20-25 mph and execute
an emergency stop to engage ABS
Keep your foot firmly on the brake even
when you feel the brake pulsate and/or
hear noise
This computerized pumping action can
pump the brakes up to 15 times per second
True or
False?

The brake pedal will vibrate when ABS is engaged.

TRUE
Many drivers release the pressure on the brake pedal
when they feel the vibration.
Taking your foot off the brake disengages the ABS


Check your Knowledge
71
1.
What factor affects perception time, reaction distance and
braking distance?
2.
Radar detector use is illegal in Virginia.
3.
In areas without a speed limit sign, the speed limit in a
residential area is:
4.
In areas without a speed limit sign, the speed limit in a
business area is: